Manipulation of algal microbiome composition with silicon-rich materials for enhanced phosphorus removal from wastewater

Abstract

Excess phosphorus (P) in wastewater effluent poses a serious threat to aquatic ecosystems and can spur harmful algal blooms. Revolving algal biofilm (RAB) systems are an emerging technology to recover P from wastewater before discharge into aquatic ecosystems. In RAB systems, a community of microalgae take up and store wastewater P as polyphosphate as they grow in a partially submerged revolving biofilm, which may then be harvested and dried for use as fertilizer in lieu of mined phosphate rock. Disclosed herein are methods for isolating and characterizing microalgae strains from active RAB systems. Strains were identified by microscopy and 16S/18S ribosomal DNA sequencing, cryopreserved, and screened for elevated P content (as polyphosphate). Seven isolated strains possessed at least 50% more polyphosphate by cell dry weight than a microalgae consortium from a RAB system, with the top strain accumulating nearly threefold more polyphosphate. Isolated P-hyperaccumulating microalgae have broad applications in resource recovery from various waste streams, including improving P removal from wastewater.

We claim: 
     
         1 . A method for enriching a microbial population capable of sequestering phosphorus and nitrogen comprising the addition of silicon rich materials to a solution wherein the microbial population is contacted with the solution. 
     
     
         2 . The method of  claim 1  wherein the silicon rich material is sand. 
     
     
         3 . The method of  claim 1  wherein the microbial population is cyclically exposed to the solution and further exposed to atmosphere. 
     
     
         4 . The method of  claim 3  wherein the atmosphere comprises carbon dioxide. 
     
     
         5 . The method of  claim 1  wherein the microbial population comprises  Chlamydomonas pulvinata  TCF-48g. 
     
     
         6 . The method of  claim 1  wherein the microbial population comprises diatoms  Eolimna minima  TCF-3d. 
     
     
         7 . The method of  claim 1  wherein the microbial population comprises  Craticula molestiformis  TCF-8d. 
     
     
         8 . The method of  claim 1  wherein the weight percent of phosphorus of the dry weight of the microbial population biomass is from about 11 percent to about 14 percent. 
     
     
         9 . A method for the removal of phosphorus from a solution comprising enriching a microbial population capable of sequestering phosphorus and nitrogen comprising the addition of silicon rich materials to a solution wherein the microbial population is contacted with the solution and further comprising isolating the microbial population and isolating phosphorus from the microbial population. 
     
     
         10 . The method of  claim 9  wherein the silicon rich material is sand. 
     
     
         11 . The method of  claim 9  wherein the microbial population is cyclically exposed to the solution and further exposed to atmosphere. 
     
     
         12 . The method of  claim 11  wherein the atmosphere comprises carbon dioxide. 
     
     
         13 . The method of  claim 9  wherein the microbial population comprises  Chlamydomonas pulvinata  TCF-48g. 
     
     
         14 . The method of  claim 9  wherein the microbial population comprises diatoms  Eolimna minima  TCF-3d. 
     
     
         15 . The method of  claim 9  wherein the microbial population comprises  Craticula molestiformis  TCF-8d. 
     
     
         16 . The method of  claim 9  wherein the weight percent of phosphorus of the dry weight of the microbial population biomass is from about 11 percent to about 14 percent.